When you say ‘hill’ the Queen interrupted, “I could show you hills, in comparison with which you’d call that a valley.” ‘No I shouldn’t’ said Alice, surprised at contradicting her at last: ‘a hill can’t be a valley, you know. That would be nonsense—.
– Through the Looking Glass, by Lewis Carroll
Consider what it would be like to meet the Red Queen. Not only is she boisterous and overbearing, but she’s also convinced that your perceptions of the world are wrong. Science often behaves like the Red Queen, leaning over to whisper a little bit of craziness in our collective ears. At first, we gawk at the nonsense spewed in our direction, yet with time, we realize that the world really does work like her majesty said. A new approach to studying crime is doing violence to our intuitions about where illegal behavior comes from. In a prior discussion, we introduced you to why this new approach was necessary.
Here, we take you further into Wonderland and acquaint you with some of what we consider to be the real underlying causes of crime. Criminology’s Wonderland is an odd place, so be warned, it only gets “curiouser and curiouser” from here on in.
As we have noted before, crime is heritable. And yet, there is no crime gene. The fact that we have to write such a qualification speaks to a woeful ignorance of genetics that pervades much of the public and academia. Mercifully, we can sidestep long discussions of molecular biology and skip right to the “law” that takes the possibility of a crime gene off the table. It is in fact, the newly dubbed “4th Law of Behavior Genetics” and it’s quite simple. For complex traits, there are, for the most part, likely hundreds or thousands of genes involved, most of which generally contribute only very small effects to any given outcome. Not only are there many genes involved, but the complexity of how these genes operate is amazing. There are genes that influence other genes, genes that assemble neurons and run them, and genes that perform any number of other banal processes in the body. The link between a gene and some behavioral outcome, moreover, doesn’t have to be linear, straightforward, or deterministic. Most importantly for our discussion, though, is that many of these genes underpin the workings of our central nervous system, an interface with the world that ultimately comes to bear on our behavior, including our behaviors that happen to break the law.
Think of it another way, when we say that crime is heritable, we mean that the reason why people differ in their propensity to engage in crime is, in part, because they differ at a genetic level from one another. Unless you have an identical twin, no one carries your unique genome (and even then, some differences can still emerge). Crime is far from the only outcome that is heritable, as virtually every other trait is partly heritable. In fact, you would be hard-pressed to identify any behavioral outcome that is not under some level of genetic influence. Criminal behavior is no exception.
We previously published a study that examined the heritability of chronic criminal behavior. Our goal for this project was to explore the role that genetic differences played in engaging in crime consistently across long stretches of the life course. What did we find? In our analysis of a national sample of Americans, genetic differences accounted for much of the reason why a small proportion of our sample persistently reported breaking the law. You might be interested to know that we also examined whether heritable differences played a role in short-term law breaking. This happens to be the type of normal delinquent behavior that most of the population engages in around puberty and then stops in early adulthood. We also tested whether genes were involved in the reason why some folks never committed a single delinquent or criminal act. For all of these outcomes, we found basically the same thing: genetic differences mattered regardless of whether people break the law for decades, for a short time, or why they never break it at all.
Like when Alice meets the queen, this is a place where the world starts to spin beneath our feet a bit. As we already mentioned, most people do not commit crime for their entire life, so what prompts the change? It mustn’t be genes, for genes never change and their effects are long lasting, right? Indeed, our own research has shown that genetic influences play an important part in stable forms of criminal behavior. Nonetheless, our findings also revealed at least some role for genes to play in changes in criminal behavior over time (her majesty chuckles just over your shoulder). How does that square with your intuitions about genetic differences and the effects that they produce?
The eyes of critics are likely rolling now, as they anticipated this first move on our part. Lest we be made into straw men at some point down the line, we do NOT think that genes are all the matter. To make such an argument would be to flout the evidence that we think is so very solid, findings from behavior genetic studies. You see, when you pull out the effects of genes, you get a nice glimpse into which part of the environment matters, and the environment clearly matters. What environment, where is it, and when does it matter? One of the more shocking bits of “nonsense” is that it’s not the environment that we think should matter. As compelling of an explanation as it may seem, the family environment just does not play a tremendous part in explaining why some kids grow up to break the law more often than others. As we’ve tried to make clear in previous essays, this is not of minor importance.
Prominent theories in the field still elevate the family environment as essential when attempting to understand behavior over a lifetime. Consider just one (controversial) example, the origins of domestic violence. Prevailing ideas about where this awful activity comes from typically implicate something about families (in the form of learning or modeling). There is simply less and less reason to think that this is the case. Our own work has shown that much of the variance in intimate partner violence is explained by genetic factors, not much of it is captured by family experiences, and the rest of it is explained by measurement error and the unique personal experiences we have over the lifetime. As a caveat, it’s completely feasible that the unique experiences that siblings have with their parents might matter a great deal (say, for instance, one child is treated differently by the parents), but then that would make parenting into a unique environmental experience, something totally distinct from a shared environmental effect.
Children experience all types of environments outside the home, and there is evidence that these experiences can and do matter in the long term. You can probably compile a list of them without too much mental strain: kids in the same family can have different social circles (comprised of different friends), different teachers at school, different hobbies, and so on. Could these differences matter? They certainly could, yet it’s worth it to dump a tiny bit of cold water on this part of the discussion before proceeding much further: even these “environments” are heritable. We don’t randomly stumble into peer groups and we don’t haphazardly pick our hobbies. Both flow—to some degree—from our natural aptitudes and abilities, which are shaped in part by our genes.
Not too long ago, the psychologists Kenneth Kendler and Jessica Baker examined a range of different “environments” to see whether hidden genetic influences might be lurking, and they were. Everything from stressful experiences to family conflict showed some degree of genetic influence, and the reasons why aren’t exactly shrouded in mystery. The same heritable personality traits influence how we react to and deal with the world and the people in it. As a result, genetic influences have a spillover effect that partly impacts the types of environments that we encounter, and how we deal with them. None of this invalidates the importance of the environment, it just means we have to account for those genetic spillovers in our research. As we’ve tried (and are trying) to make clear, most social scientists do not.
Consider a related possibility, tied to the topics discussed above. Imagine that you observe a correlation between, falling victim to crime, and also actively perpetrating it. Such correlations are not a shock to criminologists, who have at term for it: victim-offender overlap. Those in the population actively perpetrating crime are also subject to falling victim to the unlawful activities of others. Now, consider why this might happen?
It’s not a particularly intractable question. In fact it admits of a rather obvious solution, crime is risky and can turn violent and dangerous. Doing a lot of crime puts you in contact with other people who are also risky, violent, and dangerous. It’s no great shock, then, when one antisocial person victimizes another. But what if something deeper is going on? Indeed, much of the correlation between victimization and criminal involvement may in fact be explained by genetic factors (as recent research suggests). Think about it this way: the same genetic influences that have an impact on criminal involvement also may impact victimization. Curiouser and curiouser…
Nonetheless, there is mounting evidence that “nonshared” environments matter for criminal involvement, even after you extract the genetic factors that might otherwise clutter up your environmental effects. Our discussion of this is shorter, for a reason, though. Only recently have studies begun specifically testing the role that nonshared environments play in the origins of crime, and this is largely because for decades criminologists rejected the idea that genes mattered at all, so talking about nonshared effects verses genetic effects was never even considered.
This is where the logic dam begins cracking even further, and seeping out is nothing but bitter irony; anyone interested in studying the environment—regardless of their interest or disinterest in genes—has had at their disposal (short of an experiment) the most powerful tool for doing the job for decades: twin studies. And yet, criminologists have moved like a hoard of zombies in the opposite direction. Here’s the implication of that massive undead exodus headed in the wrong way, all of our knowledge about “the environment” and the role that it plays in creating criminal behavior is likely bunk. Virtually every study will need to be redone in order to pull out the genetic influence, retest the effect of the environment, and then decide whether it matters.
There is another “nonsense” possibility that you should consider, and it relates directly to the nonshared environment. Some of what happens to us in life represents pure, random chance. That’s right, you can’t always anticipate what’s around the next corner. Moreover, randomness creeps in to our development, possibly tinkering with how neurons wire and how the brain develops. Much of this randomness is impossible to study yet we know that it matters and is lurking in the shadows of what we call “nonshared” effects. So no, not everything is genetic, but that doesn’t mean that everything is predictable in the sense that we might like to imagine. As downtrodden of a prospect as it may seem, we need to prepare ourselves for the possibility that pure developmental randomness and chance play a larger role in the origins of crime than we might like to accept.
We should not close before dealing with two lingering bits of real-life, nonsense (which we also discuss here). We must talk about them again, though, because they seem to have latched themselves into the collective consciousness of the public and they simply will not budge. They are epigenetics and gene-environment interactions.
Biologically speaking, these are essential components of growth, development, and functioning. Scientifically, they represent key enterprises that hold the promise of shedding much needed insight on everything from diseases to behavior. Nonetheless, an eager public and a misinformed segment of the academy has caricatured the science and turned these two topics into nonsense. As Pinker notes, “it’s all about interactions” and other such rallying cries are used reflexively rebut discussions like this one. Do not fall into that trap.
As we’ve said countless times, both genes and the environment matter, but that does not mean that they always interact in a statistical sense, and it doesn’t mean that “everything” is an “interaction.” Writers (including the authors of this essay) continue to make this point, and yet it continues to be ignored. While there are some social scientists that argue that genetic effects can only surface when triggered by environmental stimuli, they are flat-out wrong. Yes, there is evidence indicating that genetic effects can be dependent on environmental exposure, but there is also evidence that genes can have effects on behavioral phenotypes that are fully independent of gene-environment interactions. More recently, there has been a shift to focus on epigenetic influences on crime and to argue that all genetic effects are really part of epigenetic processes. While this might be an appealing and seductive explanation, there is really no evidence in favor of it. Epigeneticists are urging caution in implicating epigenetic explanations for complex human outcomes, such as crime, but this has not deterred social scientists from throwing all of their eggs in the epigenetic basket.
If experts in the field are cautioning about the limits of their newly developing science for revealing the intricacies of human behaviors, what does that tell us about social scientists who are championing epigenetics as a key causal agent in the etiology of criminal behavior? What it means is that many of them have waded out into waters so deep, that they are now in over their heads. They don’t fully understand the limits of epigenetic research, yet they’ve uncritically embraced ideas that sound scientific and accord with their prevailing dogma. In many respects, this is predictable, because in order to cast a critical eye towards findings from a particular area of research, one would have to understand that field on an intimate level and most social scientists are not at that point with epigenetics.
You are now one level deeper into Wonderland. How does it feel? Dizzying, we’re sure, but you’ll orient yourself shortly. In a series of conversations (see for example here, here, and here), we’ve deliberately tried to do damage to your conception of what actually influences human behavior, and in particular, about where the biggest influences on crime come from. We’ve only scratched the surface, there is much left to be discussed and we’ve given you what amounts to a whirlwind tour. For the new initiate, it is enough to know that you must unlearn much of what you “know” and virtually all of how you feel about where crime comes from. We must start talking much more about genetics, we must talk much less about parental socialization, and we must accept the possibility that the causes of crime that lurk in the “non-shared environment” might be harder to splice apart than we ever imagined. This doesn’t mean it’s impossible. It’s just hard. What in life isn’t? On the genetic side of things, the march of progress is yielding studies capable of exploring those “miniscule effects” that we mentioned earlier. More time is needed, though, for this science to reach maturity.
Welcome, nonetheless, to Criminology’s Wonderland. A place where the hills are valleys, and the world spins beneath your feet. Give it some time, though, it will feel normal before you know it.
Brian Boutwell is an Associate Professor of Criminology and Criminal Justice at Saint Louis University. Follow him on Twitter: @fsnole1
Kevin M. Beaver is a Professor of Biosocial Criminology at Florida State University.